Occupancy sensors mounted in a doorjamb are known in the art. 20060176697 (application Ser. No. 11/053,554) to Arruda describes using an off-the-shelf combination light and sensor wall switch sensor that detects when the door is opened/closed to turn the light on/off in which the sensor and light are mounted together in a special structure that is mounted to or near the door frame or jamb. U.S. Pat. No. 6,023,224 to Meyvis describes a similar system that can be mounted within or to a door frame and includes a motion sensor. Sun9 offers a doorjamb mounted occupancy sensor that purports to count people entering and exiting (two different functions) so that lighting may be controlled instantaneously, particularly on exit of the last person. This is counter to typical motion-based occupancy sensors that assume a space is empty due to lack of motion (or sound or other monitored event). All of these systems suffer from the unneeded complexity of requiring special doorjambs or complicated mounting of special assemblies into or on to a door jamb.